Insulating material with renewable resource component

ABSTRACT

An insulated cabinet structure includes an inner liner having a plurality of walls defining a refrigerator compartment, and an external wrapper having a plurality of walls defining a refrigerator compartment receiving area. An insulation gap is formed between the walls of the inner liner and the walls of the external wrapper. A first insulation material is positioned on a wall of the external wrapper and extends outwardly into the insulation gap to partially fill the insulation gap. The first insulation material includes a renewable resource component having a particle size in a range from about 10 microns to about 25 microns. A second insulation material is disposed in the insulation gap, such that the first insulation material and the second insulation material together substantially fill the insulation gap.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. patent applicationSer. No. 14/964,178 (now U.S. Pat. No. 9,791,205), filed Dec. 9, 2015,entitled INSULATING MATERIAL WITH RENEWABLE RESOURCE COMPONENT, theentire disclosure of which is hereby incorporated herein by reference.

BACKGROUND

In order to provide increased efficiency for an insulated appliance,such as a refrigerator cabinet, the refrigerator cabinet must besufficiently insulated to keep items within the refrigerator cool, aswell as prevent heat from entering the refrigerator structure. Adding arenewable source component to an insulation component while lowering thecost of the overall refrigeration insulation is desired, such that newmethods and materials of insulating a refrigerator are sought.

SUMMARY

One aspect of the present concept includes an insulating member having abody portion and a core portion disposed within an interior of the bodyportion. The core portion comprises a renewable resource component in anamount of 10%-90% by weight of the core portion, and further includes aparticle size in a range from about 10 microns to about 25 microns. Anexterior portion substantially surrounds the core portion, and includesan insulating material defining a vapor barrier around the core portion.

Another aspect of the present concept includes an insulated cabinetstructure with an inner liner having a plurality of walls defining arefrigerator compartment, and an external wrapper having a plurality ofwalls defining a refrigerator compartment receiving area. An insulationgap is formed between the walls of the inner liner and the walls of theexternal wrapper. A first insulation material is positioned on a wall ofthe external wrapper and extends outwardly into the insulation gap topartially fill the insulation gap. The first insulation materialincludes a renewable resource component having a particle size in arange from about 10 microns to about 25 microns. A second insulationmaterial is disposed in the insulation gap, such that the firstinsulation material and the second insulation material togethersubstantially fill the insulation gap.

Yet, another aspect of the present concept includes an insulated cabinetstructure with an inner liner having a plurality of walls defining arefrigerator compartment. An external wrapper includes a plurality ofwalls defining a refrigerator compartment receiving area. An insulationgap is formed between the walls of the inner liner and the walls of theexternal wrapper when the inner liner is at least partially received inthe external wrapper. An insulation material is positioned in theinsulation gap to substantially fill the insulation gap, wherein theinsulation material includes a renewable resource component in an amountof about 10%-90% by weight of the insulation material. The renewableresource component includes a particle size in a range from about 10microns to about 25 microns.

These and other features, advantages, and objects of the present devicewill be further understood and appreciated by those skilled in the artupon studying the following specification, claims, and appendeddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1A is a top perspective view of a refrigerator cabinet, accordingto one embodiment;

FIG. 1B is an exploded top perspective view of the refrigerator cabinetof FIG. 1A, according to one embodiment;

FIG. 2 is a cross-sectional view taken at line II of FIG. 1A;

FIG. 3 is a schematic depiction of a refrigerator cabinet insulatorfilling system, according to one embodiment;

FIG. 4 is a schematic depiction of a refrigerator cabinet insulatorfilling system, according to one embodiment;

FIG. 5 is an exploded view of an inner liner and external wrapper,according to one embodiment;

FIG. 6 is a cross-sectional view of a refrigerator cabinet having firstand second insulation materials disposed in an insulation gap;

FIG. 7 is a cross-sectional view of a refrigerator cabinet having aplurality of insulation members disposed in an insulation gap;

FIG. 8 is a cross-sectional view of a refrigerator cabinet having aplurality of insulation panels disposed in an insulation gap;

FIG. 9 is a graphical representation of a thermal conductivity valuerelative to a pressure value; and

FIG. 10 is a graphical representation of a thermal conductivity valuerelative to a particle diameter.

DETAILED DESCRIPTION OF EMBODIMENTS

For purposes of description herein the terms “upper,” “lower,” “right,”“left,” “rear,” “front,” “vertical,” “horizontal,” and derivativesthereof shall relate to the device as oriented in FIG. 1A. However, itis to be understood that the device may assume various alternativeorientations and step sequences, except where expressly specified to thecontrary. It is also to be understood that the specific devices andprocesses illustrated in the attached drawings, and described in thefollowing specification are simply exemplary embodiments of theinventive concepts defined in the appended claims. Hence, specificdimensions and other physical characteristics relating to theembodiments disclosed herein are not to be considered as limiting,unless the claims expressly state otherwise.

Referring now to FIG. 1A, a refrigerator 10 is shown having a cabinet 12configured to generally define a refrigerator compartment 14. As shownin FIG. 1A, the refrigerator 10 is depicted as having a generallyupright rectangular configuration, but may include any configuration forrefrigerator known in the art including, but not limited to, Frenchdoor, side-by-side, top freezer, bottom freezer, freezer-less, counterdepth, compact, built-in, and other refrigerator configuration.

Referring now to FIG. 1B, the cabinet 12 is shown as including an innerliner 16 which generally defines the refrigerator compartment 14 viafirst and second sidewalls 18, 20, top wall 22, and bottom wall 24. Arear wall 26 closes the refrigerator compartment 14. A liner flange 28is disposed around the inner liner 16 and connected to the first andsecond sidewalls 18, 20, as well as the top and bottom walls 22, 24along a front portion of the inner liner 16, such that the liner flange28 defines a forward face of the inner liner 16. In the depictedembodiment of FIG. 1B, the inner liner 16 has a generally rectangularbox shape, but may take a variety of shapes including a cube, prism,parallelepiped, etc. and combinations thereof to suit a configuration ofthe refrigerator 10. The inner liner 16 may be formed from a polymericmaterial having high barrier properties (e.g., low gas permeation),metals and combinations thereof. The inner liner 16 may be formed viathermoforming, injection molding, bending and/or forming. The linerwalls 18, 20, 22, 24 and 26 of the inner liner 16 may have a thicknessranging from between about 0.1 mm to about 1.0 mm. In a specificembodiment, the liner walls 18, 20, 22, 24, and 26 are contemplated tohave a thickness of about 0.5 mm.

Referring again to FIG. 1B, the inner liner 16 is shown as beingconfigured to mate, couple, or otherwise be positioned within anexternal wrapper 30. The external wrapper 30 includes first and secondsidewalls 32, 34, top wall 36, and bottom wall 38. A rear wall 40 closesthe refrigerator compartment. Thus, the external wrapper 30 has anoverall configuration similar to that of the inner liner 16, such thatthe refrigerator compartment 14 of the inner liner 16 can be fullyreceived within a refrigerator compartment receiving area 42 defined bythe wrapper walls 32, 34, 36, 38 and 40. In a manner similar to theinner liner 16, the external wrapper 30 includes a wrapper flange 44extending around the sidewalls 32, 34 and top and bottom walls 36, 38 ata forward portion of the external wrapper 30.

In assembly, as shown in FIG. 2 and described below, the wrapper flange44 and the liner flange 28 are configured to be coupled together to formthe cabinet 12, as shown in FIG. 1A. The coupling of the liner flange 28and the wrapper flange 44 is contemplated to be performed in such amanner that an airtight or hermetic seal is formed between the innerliner 16 and the external wrapper 30. The seal of the inner liner 16 tothe external wrapper 30 may be achieved using adhesives, welding,crimping, or combinations of such coupling techniques. The externalwrapper 30 may be formed of and by any of the materials and processeslisted above in connection with the inner liner 16. The wrapper walls32, 34, 36, 38 and 40 of the external wrapper 30 may have a thicknessranging from between about 0.1 mm to about 1.0 mm. In a specificembodiment, the wrapper walls 32, 34, 36, 38 and 40 have a thickness ofabout 0.5 mm. Any one of the wrapper walls 32, 34, 36, 38 and 40 of theexternal wrapper 30 may include an injection port 50 and/or a vacuumport 52, shown in FIG. 1B as disposed on top wall 36 and sidewall 34,respectively. The external wrapper 30 may include one or multipleinjection ports 50 and/or vacuum ports 52. It will be understood that inalternative embodiments, the injection ports 50 and/or vacuum ports 52may be disposed on both the external wrapper 30 and inner liner 16, orsolely on either the inner liner 16 or external wrapper 30. Theinjection port 50 and the vacuum port 52 may be used to access (e.g., toinject an insulator, draw a vacuum and/or perform maintenance within) aninsulation gap 54 formed between the refrigerator compartment 14 and therefrigerator compartment receiving area 40 once the inner liner 16 andthe external wrapper 30 are bonded. The injection port 50 and the vacuumport 52 may have a diameter of between about 10 mm and about 30 mm, orbetween about 12.5 mm and about 25 mm. In various embodiments, theinjection port 50 and the vacuum port 52 may have different diametersthan one another. Similarly, in embodiments utilizing more than oneinjection port 50 and vacuum port 52, the sizes of the injection ports50 and the vacuum ports 52 may vary. The insulating material 80 ispositioned within the insulation gap 54 and in contact with both thewrapper walls 32, 34, 36, 38 and 40 and the liner walls 18, 20, 22, 24and 26. The packing factor of the insulating material 30 within the gap26 may be greater than about 60%, greater than about 62%, greater thanabout 65%, or greater than about 70%.

The insulating material 80 is configured not only to thermally insulatethe inner liner 16 from the external wrapper 30, but also to resist theinward directed force of the atmosphere on the lower than atmospherepressure of the insulation gap 54. Atmospheric pressure on the innerliner 16 and the external wrapper 30 may cause distortions which areunsightly and may lead to a rupture in either of the inner liner 16 orthe external wrapper 30 thereby causing a loss of vacuum in theinsulation gap 54. Further, drawing the vacuum in the insulation gap 54may cause an impact or shock loading of the insulating material 80 asthe inner liner 16 and the external wrapper 30 contract around theinsulating material 80. Accordingly, the insulating material 80 shouldhave sufficient crush resistance to resist deformation of the innerliner 16 and the external wrapper 30 due to a pressure gradient betweenthe atmosphere and an air pressure of the insulation gap 54. Theinsulating material may also serve as a sound dampening mechanism inassembly.

Referring again to FIG. 1B, an exterior shell 60 may also be included inthe formation of the cabinet 12, wherein the exterior shell 60 includesfirst and second side walls 62, 64 as well as top wall 66 and rear wall68. The first and second sidewalls 62, 64 and top wall 66 are configuredto align with an outer perimeter of the liner flange 28 and wrapperflange 44 as coupled together. The exterior shell 60 generally defines acabinet receiving area 70 which is configured to receive the inner liner16 and external wrapper 30 as coupled together therein.

Referring now to FIG. 2, the inner liner 16 and external wrapper 30 areshown coupled together, such that the refrigerator compartment 14 isreceived within the refrigerator compartment receiving area 42, therebydefining the insulation gap 54 therebetween. The insulation gap 54 isconfigured to receive an insulator material 80. The insulation gap 54may have a thickness of between about 12 mm to about 22 mm. Theinsulation gap 26 may have an air pressure of less than about 1 atm(101,325 Pa), less than about 0.5 atm (50,662.5 Pa), less than about 0.1atm (10,132.5 Pa), less than about 0.001 atm (101.325 Pa) or less thanabout 0.00001 atm (1.01 Pa). The insulating material 80 may be amaterial configured to have low thermal conductivity. For example, theinsulating material 80 may include precipitated silica, polyurethanefoam, fumed silica, beads (e.g., of glass, ceramic, and/or an insulativepolymer), hollow organic spheres, hollow inorganic spheres, renewablematerials, processed renewable materials, and combinations thereof.Optionally, an opacifier (e.g., TiO₂m SiC and/or carbon black) may beincluded in the insulating material 80 or materials configured to changethe flow properties and packing factor of the insulating material 80.

Referring now to FIG. 3, one embodiment of an apparatus and method ofinserting the insulating material 80 within the insulation gap 54 isdepicted. As shown in FIG. 3, the inner liner 16 is positioned withinthe external wrapper 30 as explained in greater detail above. The linerflange 28 and the wrapper flange 44 are contemplated to be bonded so asto create an airtight insulation gap 54 defined between the inner liner16 and the external wrapper 30. A vacuum is created by drawing the airout of the insulation gap 54 through the at least one vacuum port 52,wherein the vacuum provides a negative pressure relative to theatmospheric pressure. A pump, or other suitable vacuum source, may beconnected to the vacuum port 52 to facilitate the drawing and creationof the vacuum. Additionally, a vacuum chamber 90 may be used to providethe vacuum to the insulation gap 54.

With further reference to FIG. 3, injecting the insulating material 80into the insulation gap 54 is contemplated to be accomplished by feedingthe insulating material 80 into a hopper 82 which in turn supplies theinsulating material 80 to a powder pump 84. The powder pump 84 pumps orotherwise injects the insulating material 80 into the insulation gap 54.The powder pump 84 may utilize fluidization of the insulating material80 to move the insulating material 80 into the insulation gap 54. Thepowder pump 84 may dispense the insulating material 80 into theinsulation gap 54 under or without pressure. Use of the powder pump 84allows the insulating material 80 to be inserted into the insulation gap54 without any densification or compaction, while also providing anefficient means of depositing the insulating material 80 in theinsulation gap 54. Vibration techniques may be used to vibrate the innerliner 16 and/or the external wrapper 30 in an effort to increase thepacking factor of the cause the insulating material 80 as disposedwithin the insulation gap 54. The inner liner 16 and/or external wrapper30 may be supported by one or more supports 86, such that relativemotion between the inner liner 16 and the external wrapper 30 isminimized or prevented. The supports 86 may allow the thickness of theinsulation gap 54 to remain constant through filling and vibration.

Referring now to FIG. 4, another method of dispensing the insulatingmaterial 80 within the insulation gap 54 between the inner liner 16 andthe external wrapper 30 is shown. In this method, dispensing of theinsulating material 80 into the insulation gap 54 may be accomplishedthrough an access aperture 92. The back aperture 92 may take a varietyof shapes (e.g., square, rectangular, circular, oblong, and combinationsthereof) and sizes which are configured to allow the insulating material80 to be poured or otherwise deposited into the insulation gap 54. Theinsulating material 80 may be positioned in the insulation gap 54between the inner liner 16 and the external wrapper 30 via a powderpump, such as powder pump 84 described above with reference to FIG. 3.Further, the insulating material 80 may be positioned in the insulationgap 54 by pouring a mixture containing the insulating material 80 intothe insulation gap 54. The insulating material 80 may be positioned inthe insulation gap 54 by spraying a foaming mixture containing theinsulating material 80 into the insulation gap 54. Further, theinsulating material 80 may be positioned in the insulation gap 54 bycreating blocks or panels containing the insulating material 80, andpositioning these blocks and/or panels in the insulation gap 54. Oncethe insulation gap 54 between the inner liner 16 and the externalwrapper 30 is filled with the insulating material 80 and sufficientlypacked, a cover 94 is positioned over the access aperture 92. The cover94 may be constructed of the same or similar material as the externalwrapper 30, or a different material. Once the cover 94 is positionedover the access aperture 92, the cover 94 is sealed to the externalwrapper 30 to form an airtight, or hermetic, seal. With the airtightseal in place, a vacuum can be drawn within the insulation gap 54 in amanner as described above. The vacuum may be drawn through the vacuumport 52 (FIG. 3) of the external wrapper 30. Additionally, this methodcan also be conducted in a vacuum chamber 90.

Referring now to FIG. 5, another embodiment of a cabinet 12A is shown inan exploded view with an inner liner 16A which generally defines arefrigerator compartment 14. The inner liner 16A includes a number ofcomponents similar to inner liner 16 described above with like referencenumerals, such as first and second sidewalls 18, 20, top wall 22 andbottom wall 24. A rear wall 26 closes the refrigerator compartment 14. Aliner flange 28 is disposed around the inner liner 16A along a frontportion thereof. The cabinet 12A further includes an external wrapper30A. The external wrapper 30A includes a number of components similar toexternal wrapper 30 described above with like reference numerals, suchas first and second sidewalls 32, 34, top wall 38 and rear wall 40.Thus, the external wrapper 30A has an overall configuration similar tothat of the inner liner 16A, such that the refrigerator compartment 14of the inner liner 16A can be fully received within a refrigeratorcompartment receiving area 42 defined by the wrapper walls 32, 34, 36and 40. The external wrapper 30A includes a wrapper flange 44 disposedat a forward portion of the external wrapper 30A.

As further shown in FIG. 5, the sidewall 32 of the external wrapper 30Aincludes an insulation member 102 disposed thereon. Similarly, sidewall34 and top wall 36 also include insulation members 104, 106,respectively, disposed thereon, which are shown in phantom in FIG. 5.Rear wall 40 of the external wrapper 30A also includes an insulationmember 108 disposed thereon. The insulation members 102, 104, 106 and108 are disposed on inwardly facing surfaces, such that the insulationmembers 102, 104, 106 and 108 are configured to be disposed in theinsulation gap 54 disposed between the inner liner 16A and externalwrapper 30A, as best shown in FIG. 6.

As shown in FIG. 6, a cross-sectional view of the refrigerator cabinet12A separately illustrates three embodiments for the insulation members,with insulation member 102 in a board form, insulation member 104 in apowder form, and insulation member 108 as loose fiberglass. Eachinsulation member 102, 104 and 108 are shown covered by barrier sheets112, 114, and 118 respectively. The barrier sheets 112, 114, and 118 arecontemplated to be metallic foil sheets that can be formed from either aferrous or non-ferrous material. Of course, although a metallic materialis preferred, the barrier sheets 112, 114, and 118 can also be formedfrom non-metallic materials without departing from the spirit of thepresent concept. When placed upon the insulation members 102, 104 and108, the sheets 112, 114, and 118 define upper surfaces that protect theinsulation members 102, 104 and 108 from water vapor and other likedestructive materials. When the refrigerator cabinet 12A is assembled toform the insulation gap 54 (in which the insulation members 102, 104 and108 are disposed), a second insulation material 122, preferablypolyurethane foam, is contemplated to be injected between each barriersheet 112, 114, and 118 and the outer walls of the inner liner 16A, suchthat a composite insulation arrangement is formed. Once secondinsulation material 122 cures, it will not only provide additionalinsulation for the cabinet 12A, but it will add structural integritythereto as well. The second insulation material 122 may include silicaor other porous material capable of supporting the cabinet structurewhen a vacuum is formed. It is further contemplated that the insulationmembers 102, 104 and 108 may substantially fill the entire insulationgap 54 on their own, such that a second insulation material is notnecessary. As further shown in FIGS. 5 and 6, evacuation tubes 120 areshown as coupled to each of the insulation members 102, 104 and 108, andmay be use to form a vacuum around the insulation members 102, 104 and108. While insulation members 102, 104 and 108 are shown in FIG. 6 ashaving varying forms, it is contemplated that the insulation members102, 104 and 108 may also be of a similar form, such as an insulationpanel.

Referring now to FIG. 7, a crossectional view of another refrigeratorcabinet 12B is shown, wherein an inner liner 16B is coupled to anexternal wrapper 30B to form an insulation gap 54 therebetween.Insulation members 124 are shown disposed in the insulation gap 54 toinsulate the refrigerator compartment 14. The insulation members 124shown in FIG. 7 are contemplated to be insulation blocks formed from amulti-component insulating material in a press or mold forming process,as further described below.

Referring now to FIG. 8, a crossectional view of another refrigeratorcabinet 12C is shown, wherein an inner liner 16C is coupled to anexternal wrapper 30C to form an insulation gap 54 therebetween.Insulation members 126, 128 and 130 are shown disposed in the insulationgap 54 to insulate the refrigerator compartment 14 defined by thecabinet 12A. The insulation members 126, 128 and 130 are shown in FIG. 7as insulation panels having core portions 126A, 128A and 130A disposedwithin outer portions 126B, 128B, 130B to form multi-componentinsulating structures with varying properties between the cores 126A,128A and 130A and outer portions 126B, 128B, 130B, as further describedbelow.

The insulating materials used for the present concepts will now bedescribed. As noted above, the insulation material used with the presentconcept is contemplated to provide a renewable resource, orenvironmentally friendly resource, as a component part of the insulationcomposition. This measure not only provides for more environmentallyfriendly insulating practices, but also can save on the costs involvedin properly insulating a refrigerator cabinet as compared to standardpolyurethane foams. Specifically, the cost of an insulation made with arenewable resource may cost about $0.10 per kilogram as compared toabout $2.419 per kilogram of polyurethane foam. Often times theinsulation made with the renewable resource exemplifies a similarinsulating property or may include only a 5% heat gain as compared topolyurethane foam materials. As used herein, the terms “renewableresource component” or “renewable resource” refer to filler materialsthat are eco-friendly materials, such as an organic material, a biomassmaterial, a natural waste by-product of a particular industry, or otherlike naturally occurring component.

One renewable resource contemplated for use as an organic component ofthe insulating materials of the present concept are rice husks or ricehulls which are the hard protective outer coverings of grains of rice.Rice husks are a thermal insulating material comprised of approximately70-75% silica. Using thermal treatments, the silica percentage in ricehusks can be increased to approximately 90-98%. Silica is a knowncompound that is one of the better insulators used in vacuum insulationpanels and other high performance thermal insulation applications.Preparing rice husks for use in an insulation material may include thefollowing steps:

1) washing rice husks in distilled water;

2) drying the rice husks in hot air at 60 degrees Celsius forapproximately sixty minutes;

3) sizing the rice husks using an industrial grinder;

4) mixing rice husks with a binding resin at a ratio of approximately2:1 rice husks to resin by weight;

5) stirring the rice husks in biding resin to properly mix thecomposition;

6) comparing insulating blocks using a press and mold with thecomposition; or

7) preparing panels for use as vacuum insulation panels with thecomposition.

The rice husk, or a composition containing rice husks, may be passedthrough a sieve of about 10 microns to about 25 microns to achieve aparticle size optimal for using rice husks as a renewable resourcecomponent in an insulating material. With a rice husk particle size ofabout 10 microns to about 25 microns, a thermal conductivity value ofapproximately 20-22 mW/mK is achieved as compared to a standardpolyurethane foam having a thermal conductivity value of about 17.5mW/mK to about 20.5 mW/mK.

Coconut husks are also a renewable resource considered for use with theinsulating materials of the present concept. Like the rice husks,coconut husks are a good thermal insulating material because they aredifficult to burn and less likely to allow moisture to propagate moldand fungi in an application. Historically, coconut husks have been usedin making insulation boards using a urea formaldehyde resin. In order toeliminate this synthetic resin, it is contemplated that the presentconcept will use lignin in the coconut husks as an intrinsic resin inboard production, thereby eliminating the need for chemical binders andother additives. A insulating product using coconut husks may exhibitinsulating properties in a range of about 54-143 mW/Mk.

Another renewable resource contemplated for use with the present conceptare corn cobs and corn stalks. Corn cobs and corn stalks can be used tomake particle boards and fiber boards and have been tested for use asraw materials for low density boards made using a hot press method alongwith a urea formaldehyde resin. Such boards exhibit a high mechanicalstrength and have a thermal conductivity of approximately 96 mW/mK.

Another renewable resource contemplated for use with the present conceptis durian peel. Durian peel is the outer covering of a durian fruit, andis a waste product of the durian industry. Particle boards made using adurian peel have exhibited a thermal conductivity in the range ofapproximately 64-159 mW/mK.

Another renewable resource contemplated for use with the present conceptis bagasse. Bagasse is the crushed and processed cane stalk of sugarcane that is left when the juice is collected from a sugar cane harvest.Bagasse is a waste produce of the sugar cane industry that can be usedas a raw material for making medium density fiber boards or particleboards, as well as high density hard boards. Bagasse can be furtherfortified using a phenolic resin, thereby producing boards and panelsthat are strong and durable, as well as heat and moisture resistant.These boards can be lightweight and easily transportable and exhibitthermal conductivity properties suitable for use with the presentconcept in a thermal conductivity range of about 46-51 mW/mK.

Another renewable resource contemplated for use with the present conceptis a bi-product from the palm oil production process. Oil palm leavesinclude large amounts of ligno-cellulose having a high fiber yield andare known for use in making composite panels and particle boards. Such acomposite panel may have a thermal conductivity of approximately 127mW/mK made by mixing oil palm leaves with granular wood glue in a 1:4ratio by weight. The present concept is contemplated to use theligno-cellulose component of the oil palm leaves to make a binder freefiber board using a steam expulsion method. Such a resulting insulatingmaterial would be environmentally friendly by not incorporating a toxicglue, and would also provide insulating properties similar to those ofan insulation panel made by mixing oil palm leaves with wood glue. Theabove-identified organic components are integrated into insulationproducts to provide a renewable resource component within the product.

Processes for incorporating a renewable resource component into aninsulating material will now be described, and particularly, rice husksare identified below as the incorporated renewable resource, however, itis contemplated that any of the renewable resources noted above can beused with the methods described below. The first method of incorporatinga renewable resource into an insulating product is the mixing of therenewable resource component with the components of a polyurethane foam.In this concept, rice husks and polyurethane foam are mixed in optimizedratios to deliver improved thermal insulating properties as compared toa rice husk insulation alone. Mixing the rice husk with a polyurethanefoam eliminates the need for additional binder as the component parts ofa polyurethane foam will act as a binder in the mixing process. Thepolyurethane form also adds structural rigidity as compared to rice huskinsulation alone. In making a standard polyurethane foam, isocyanate andpolyols are mixed generally in a spraying process to create a urethanefoam. Processed rice husks having a particle size of approximately 10-25microns can be incorporated into either the isocyanate mixture or thepolyol mixture before they are combined to form a urethane. Further, theprocessed rice husks can be combined with the isocyanate and polyolmixture immediately after the isocyanate and polyol components aremixed. Using the present concept, it is contemplated that a resultingpolyurethane foam would contain approximately 10-90 percent or 40-60percent by weight of the rice husk mixture which would be distributeduniformly throughout the resulting polyurethane foam. The addition ofthe rice husk in the polyurethane foam provides for a lower cost productthat is lighter than the polyurethane foam alone. Further, as notedabove, the processed rice husk component will reduce the costs of theoverall insulating product. Similarly, the rice husks can be mixed withother synthetic closed cell insulation products, such as cyclopentanefoam products and are contemplated to exhibit comparable compressionstrengths as compared to such products made without a renewablecomponent.

Another method involves providing a mixture of a renewable resource witha binder, wherein the resulting mixture is poured into an insulationgap, such as insulation gap 54 described above, for forming aninsulating product that can fill the insulation gap in a cabinet. Thismethod provides for environmentally friendly insulation without anypolyurethane foam, such that the cost of the resulting insulationproduct are reduced. In this concept, processed rice husk particles ofapproximately 10-25 microns are mixed with a resin, such as an epoxyresin, for forming a pourable mixture. Suitable epoxy resins includeepoxy cements, cross-linked polyvinyl alcohol and polyacrylamide andother cross-linked polymers that will not compact or densify theprocessed rice husk when mixed therewith. The resulting mixture can bepoured into an insulation gap, such as insulation gap 54 shown in FIG. 4using access aperture 92.

Another method used with the present concept is to use processed ricehusks as packed in insulation panels which are then vacuumed. Thisconcept involves using processed rice husks instead of fumed silica,glass fibers or precipitated silica. The resulting product provides foran insulation material that does not require additional binder and isless expensive than a standard polyurethane foam. A variation of thermalconductivity as it relates to internal pressure of such an insulationpanel is noted below in Table 1.

TABLE 1 Internal Pressure (mbar) Thermal Conductivity (mW/mK) 1000 22.0500 21.8 100 20.3 50 18.7 10 12.3 5 9.4 1 5.6

The values noted in Table 1 above are also shown in FIG. 9 of thepresent disclosure.

Another method of using a renewable resource with an insulating productof the present concept is to create an insulating product having apolyurethane foam blanket or outer portion wrapped around a core portioncreated using a renewable resource. As noted above, and further shown inFIG. 10, the particle size of the rice husks used with the presentconcept is contemplated to be between 10 and 25 microns. As shown inFIG. 10, a particle diameter of 10-25 microns results in a thermalconductivity value of approximately 22-22.2 mW/mK. Rice husks have anopen cell structure, such that an insulating product prepared using ricehusk alone is susceptible to increased thermal conductivity when exposedto water vapor or water permeation through a liner or wrapper in arefrigerator cabinet. This is because as water vapor, or any othermoisture source, is exposed to the open cell structure of a rice husk,the water can be absorbed by such an insulating product, therebyincreasing the solid conduction of the rice husk insulation product.With an increase in thermal conductivity of such a rice husk insulationproduct, the thermal performance of a refrigerator or insulation box maybe compromised. Thus, a polyurethane foam blanket around a rice huskprepared core would provide a closed cell structure for an outer portionof a panel (or other like structure) that will not allow water vapor topermeate inside into the rice husk core. The rice husk core may be apowered insulation used in the process described above with reference toFIG. 3, wherein a powered product is injected into the insulation gap 54of a cabinet 12. With reference to FIG. 8, the rice husk insulationwould generally comprise a core portion 126A having an open cellconfiguration susceptible to higher thermal conductivity when exposed towater vapor. As further shown in FIG. 8, the core portion 126A iswrapped by an outer covering 126B which is contemplated to be comprisedof a polyurethane foam which is a closed cell structure that will notallow water permeation, such that the core portion 126A retains itsinsulating properties. As noted above, a rice husk insulation product isless expensive than a standard polyurethane product, such that a panelhaving a rice husk insulating core wrapped by a polyurethane blanket,will result in an overall panel that is less expensive than a standardclosed cell panel made entirely of polyurethane products.

It will be understood by one having ordinary skill in the art thatconstruction of the described device and other components is not limitedto any specific material. Other exemplary embodiments of the devicedisclosed herein may be formed from a wide variety of materials, unlessdescribed otherwise herein.

For purposes of this disclosure, the term “coupled” (in all of itsforms, couple, coupling, coupled, etc.) generally means the joining oftwo components (electrical or mechanical) directly or indirectly to oneanother. Such joining may be stationary in nature or movable in nature.Such joining may be achieved with the two components (electrical ormechanical) and any additional intermediate members being integrallyformed as a single unitary body with one another or with the twocomponents. Such joining may be permanent in nature or may be removableor releasable in nature unless otherwise stated.

It is also important to note that the construction and arrangement ofthe elements of the device as shown in the exemplary embodiments isillustrative only. Although only a few embodiments of the presentinnovations have been described in detail in this disclosure, thoseskilled in the art who review this disclosure will readily appreciatethat many modifications are possible (e.g., variations in sizes,dimensions, structures, shapes and proportions of the various elements,values of parameters, mounting arrangements, use of materials, colors,orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter recited. For example,elements shown as integrally formed may be constructed of multiple partsor elements shown as multiple parts may be integrally formed, theoperation of the interfaces may be reversed or otherwise varied, thelength or width of the structures and/or members or connector or otherelements of the system may be varied, the nature or number of adjustmentpositions provided between the elements may be varied. It should benoted that the elements and/or assemblies of the system may beconstructed from any of a wide variety of materials that providesufficient strength or durability, in any of a wide variety of colors,textures, and combinations. Accordingly, all such modifications areintended to be included within the scope of the present innovations.Other substitutions, modifications, changes, and omissions may be madein the design, operating conditions, and arrangement of the desired andother exemplary embodiments without departing from the spirit of thepresent innovations.

It will be understood that any described processes or steps withindescribed processes may be combined with other disclosed processes orsteps to form structures within the scope of the present device. Theexemplary structures and processes disclosed herein are for illustrativepurposes and are not to be construed as limiting.

It is also to be understood that variations and modifications can bemade on the aforementioned structures and methods without departing fromthe concepts of the present device, and further it is to be understoodthat such concepts are intended to be covered by the following claimsunless these claims by their language expressly state otherwise.

The above description is considered that of the illustrated embodimentsonly. Modifications of the device will occur to those skilled in the artand to those who make or use the device. Therefore, it is understoodthat the embodiments shown in the drawings and described above is merelyfor illustrative purposes and not intended to limit the scope of thedevice, which is defined by the following claims as interpretedaccording to the principles of patent law, including the Doctrine ofEquivalents.

What is claimed is:
 1. A method of making an insulated cabinet, themethod comprising the steps of: forming an external wrapper having acavity; forming an inner liner having a refrigerator compartment;positioning the refrigerator compartment of the inner liner within thecavity of the exterior wrapper, thereby forming an insulation gapbetween the inner liner and the external wrapper; providing a renewableresource component; sizing the renewable resource component to provideparticles having a diameter of about 10 to about 25 microns; forming aninsulation member using the particles of the renewable resourcecomponent; and positioning the insulating member in the insulation gap.2. The method of claim 1, wherein the step of providing a renewableresource component further includes: providing an amount of rice huskmaterial.
 3. The method of claim 2, wherein the step of forming aninsulation member further includes: intermixing the particles of therenewable resource with a binder to form a mixture.
 4. The method ofclaim 3, wherein the step of positioning the insulating member in theinsulation gap further includes: pouring the mixture into the insulationgap.
 5. The method of claim 1, wherein the step of forming an insulationmember further includes: forming a core using the renewable component.6. The method of claim 5, wherein the step of forming an insulationmember further includes: wrapping the core with an exterior portion,wherein the exterior portion includes a closed cell structure that isimpermeable to moisture.
 7. The method of claim 1, wherein the step offorming an insulation member further includes: intermixing the renewableresource with one of a polyol component and an isocyanate component. 8.The method of claim 7, wherein the step of forming an insulation memberfurther includes: spraying the polyol component and the isocyanatecomponent into the insulation gap to intermix the polyol component andthe isocyanate component to form a foam insulation member.
 9. The methodof claim 1, wherein the step of forming an insulation member furtherincludes: forming an insulation member wherein the renewable resourcecomponent includes a thermal conductivity value in a range from about 20mW/mK to about 22 mW/mK.
 10. The method of claim 9, wherein the step offorming an insulation member further includes: forming an insulationmember wherein the renewable resource component includes a thermalconductivity value in a range from about 17.5 mW/mK to about 20.5 mW/mK.11. A method of making an insulated cabinet, the method comprising thesteps of: forming an external wrapper having a cavity; forming an innerliner having a refrigerator compartment; positioning the refrigeratorcompartment of the inner liner within the cavity of the exteriorwrapper; forming an airtight insulation gap between the inner liner andthe external wrapper by sealing a portion of the inner liner to aportion of the external wrapper; providing particles of a renewableresource component, wherein the particles include a diameter of about 10to about 25 microns; forming an insulation member using the particles;positioning the insulating member in the insulation gap; and drawing avacuum in the insulation gap.
 12. The method of claim 11, wherein thestep of providing particles of a renewable resource component furtherincludes: particles having a thermal conductivity value in a range fromabout 20 mW/mK to about 22 mW/mK.
 13. The method of claim 12, whereinthe step of providing particles of a renewable resource componentfurther includes: particles having a thermal conductivity value in arange from about 17.5 mW/mK to about 20.5 mW/mK.
 14. The method of claim11, wherein the step of forming an insulation member further includes:forming a core using the particles.
 15. The method of claim 14, whereinthe step of forming an insulation member further includes: wrapping thecore with an exterior portion.
 16. The method of claim 15, wherein thecore includes an open cell structure.
 17. The method of claim 16,wherein the exterior portion includes a closed cell structure.
 18. Themethod of claim 11, wherein the step of forming an insulation memberfurther includes: intermixing the particles of the renewable resourcewith one of a polyol component and an isocyanate component.
 19. Themethod of claim 18, wherein the step of forming an insulation memberfurther includes: spraying the polyol component and the isocyanatecomponent into the insulation gap to intermix the polyol component andthe isocyanate component to form a foam insulation member.